The headline writer at Info World catches the essence of the case: A skank discussion: Privacy, anonymity, and misogyny
Skank specifically refers to a disreputable woman, there are very serious consequences for a woman who is successfully labeled as a skank. For a professional model those consequences might very well include the loss of opportunities to represent certain brands. From little lies big lies grow. She was justified in her suit and the courts acted appropriately in my judgment.
From the comments at Boing Boing
Technically, the model has a case because calling someone a skank or ho is a statement and truth can be measured (is she having sex for money or is she excessively promiscuous?) while if she'd flat-out just called her a bitch it would have been an opinion. It is also a statement that can easily be shown to affect the model financially - if she wasn't being hired for jobs where the employers objected to that kind of behavior, or if a morals clause in a contract kicked in. Reputation can be very important in those situations. It is also clear that the intent was malicious.
But let me also point something out: this is cyberbullying on behalf of the fashion student, and it's not cool, and I would 100 times prefer than no one get to be anonymous on the internet than we choose to do nothing about cyberbullying - even between adults, where we otherwise expect them to "just get over it."
Edit ii -
Dan Gillmor has some thoughts on the matter.